Sway arrestor for a three point hitch

ABSTRACT

A three point hitch sway arrestor for limiting the lateral sway of the lower draft arms when they are disconnected from an implement and raised to the transport position on the tractor.

United States Patent 1 Haupt 11 3,709,304 [451 Jan. 9, 19 73 [54] SWAYARRESTOR FOR A THREE POINT HITCH [75] Inventor: Robert C. Haupt,Milwaukee, Wis.

[73] Assignee: Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

[22] Filed: Dec. 28, 1970 [21] App1.No.: 101,814

[52] US. Cl ..l72/450, 280/474 [51] Int. Cl. ..A0lb 59/043 [58] Field ofSearch ..280/474; 172/450 [56] References Cited UNITED STATES PATENTS3,503,625 Muller et al. ..l72/450 X 2,935,147 5/1960 Edrnan et al. 172/450 3,627,060 12/1971 Lemmon 3,047,076 7/1962 Wier et a1 2,987,1266/1961 Horney 1 72/450 Primary Examiner-Leo Friaglia Attorney-Arthur L.Nelson, Kenneth C. McKivett and Robert B. Benson [57] ABSTRACT A threepoint hitch sway arrestor for limiting the lateral sway of the lowerdraft arms when they are disconnected from an implement and raised tothe transport position on the tractor.

10 Claims, 5 Drawing Figures PATENTEDJAN ems 3 709304 SHEET 1 [IF 2 SWAYARRESTOR FOR A THREE POINT HITCH This invention relates to a three pointhitch and more particularly to a sway limiting device for the lowerdraft arms of the hitch when the hitch is disconnected from theimplement and the draft arms are raised to the transport position.

A draft vehicle which uses a three point bitch is connected to theimplement through the hitch while the implement provides a spacingbetween the rear ends of the lower draft arms. Since the lateraldimension between the rear ends of the lower draft arms is controlled bythe implement, the bearing of the draft arms against the side of thehanger brackets for supporting the draw bar prevents the swaying of theimplement.

The draft arms are universally connected at their forward ends to thetractor and also connected for power lift through the lift links to therock arms so that the lower draft arms are free to sway laterally whenthe implement is disconnected. Accordingly, means such as chains, links,springs, or similar devices have been used when the implement is notattached to the draft arms to limit the swinging movement of the lowerdraft arms relative to the tractor and prevent the lower draft arms fromswinging into the rear tractor tires causing possible damage to thedraft arms or tires. These previously used devices have been relativelyexpensive and required extra parts in an already crowded area to furthercomplicate the structure which has a tendency to interfere with hitchoperation. Accordingly, the present invention provides for improvedmeans for guiding the lower draft arms to a sway restricted positionwhen no implement is attached and the draft arms are in the raisedtransport position.

Accordingly, this invention includes cammed surfaces for engaging thelower draft arms. The cam structure is formed in such a manner thatalthough the lower draft arms are universally connected on their forwardend when they are raised with the implement detached they bear againstthe cam surfaces which biases the arms in an inward direction to moveupwardly within confined limits. It is further understood that althoughthe draft arms are not connected together on the rearward ends tomaintain a predetermined relative spaced relation the sway blocksconnected to the hanger brackets for supporting the draw-bar provide ameans whereby the lower draft arms are prevented from swaying inwardly.Accordingly, the arms are confined to a very limited lateral movementbetween the cam structure on the outer side and the sway blocks on theinner side to maintain limited lateral movement of the lower draft armswhen they are raised to the travel position.

Accordingly, it is an object of this invention to provide a swaylimiting device for a three point hitch on a tractor.

It is another object of this invention to provide a sway limiter on athree point hitch for a draft vehicle with camming surfaces on theoutboard side of the lower draft arms confining the lateral movementduring the upward movement of the draft arms with the implementdetached.

It is a further object of this invention to provide a sway limiter on athree point hitch wherein means on the rear end of the tractor defines acammed surface for camming the lower draft arms inwardly while the swayblocks prevent excessive inward swaying movein maintaining asubstantially vertical movement of the draft arms as they engage thesway blocks. Accordingly, the lateral movement of the draft arms isarrested by the cammed structure and the sway blocks to preventexcessive swaying movement of the draft arms in the upper transportposition.

Referring to the drawings, the drawings illustrate the I preferredembodiment of this invention.

FIG. 1 illustrates a three point bitch on a tractor.

FIG. 2 is an enlarged side view of the forward portion of the draft armsand sway restricter.

FIG. 3 is an enlarged view partially in section taken on line III-III ofFIG. 2.

FIG. 4 is a view taken on line lV-IV of FIG. 3.

FIG. 5 is a view taken on line VV of FIG. 3.

Referring to FIG. 1 a three point hitch is shown mounted on the tractor.Lower draft arms 1 and 2 are universally connected on the forward endsto the chassis of the tractor. Draft arm 1 is shown connected tospherical surface 17 on the spherical sleeve 18. Each draft arm isconnected to a lift link 3 and 4 respectively. The rock shaft 5 carryingthe rock arms 6 and 7 raise the lift links 3 and 4 and the draft arms 1and 2 respectively.

As the lower draft arms 1 and 2 are raised, the wear plate 8 engages thetwo piece sway block 10 and 11. The sway blocks 10 and 11 define asubstantially vertical surface which limits the inward swaying movementof arm 1. Upon the raising of the lower draft arms if theyare swung toan outward lateral position they will be cammed'inwardly by the cammingsurfaces. The left hand rear axle housing carries the lever 19 whichforms the cam 20 on the portion that extends downwardly to supportarm 1. Cam 20- defines a cammed surface 14 converging inwardly andupwardly which biases the lower draft arm 1 to a laterally inwardposition as it is raised to the transport position. Since the right andleft hand sides of the tractor are symmetrical it is believed adequateto describe only the left hand side.

The lever 19 is carried on thetorsion tube 21 which in turn is fastenedto the torsion bar 22. The torsion tube 21 encircles the torsion bar 22and is joumaled on both ends in the rear axle housing 23. The lever 19forms an eccentric mounting for the pin 1 18 on the left hand side and asimilarly mounted pin on the right hand side causing a rotationalmovement on the torsion tube 21 under draft load. The torque applied tothe torsion tube 21 is transmitted to torsion bar 22when a draft load isapplied to the lower draft arms.

The operation of the device will be described in the followingparagraphs.

When the rock shaft 5 is pivoted the rock arms 6 and 7 lift the links 3and 4 to raise the lower draft arms 1 and 2. The lower draft arm 1 movesupwardly and is cammed inwardly by the cam surface 14 and is alsoengaged on its inner surface through the wear plate 8 by the sway blocks10 and 11. With the draft arms in the raised transport position, thelateral sway is arrested by the cams and the sway blocks.

When the lower draft arms 1 and 2 are in the lowered position which isnormally the operating position they are below the cams. In thisposition, the implement controls the spacing between the rear ends ofthe draft arms 1 and 2. With the spacing between the draft arms fixedthe sway blocks on the sides of the hanger bracket 30 controls theswaying movement of the implement during operation.

When the implement is detached, however, the draft arms are free tosway. Their swaying movement inwardly is still confined by the swayblocks. The lateral outward movement of the draft armsin this positionis not limited since they are then free to sway outwardly and engage thetires and possibly cause damage to the lower draft arms or the tires.Accordingly, the draft arms are lifted when the implement is detached.With the lifting of the draft arms each draft arm is cammed by a matingcam surface which biases the draft arm to a laterally inward position asshown. It is noted that the cam 20 extends outward sufficiently toengage the draft arm and cause it to be biased inwardly as it is raised.The sway blocks continue to engage the draft arm on the inward side. Theupward movement is then confined between the vertical portion of thecammed surface and the cam supporting means and the sway blocks 10, 11and swaying is arrested in the raised or transport position as shown inFIG. 2.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. 'A sway limiting device for use with a vehicle three point hitchcomprising, a pair of rock arms, a pair of lower draft arms, connectingmeans adapted for universally connecting said lower draft arms to avehicle, a single lift link connected between each one of said rock armsand its mating lower draft arm, inner sway limiting means between saiddraft arms limiting the inward sway of said draft arms, cam meansdefining a curved surface in spaced relation rearwardly from saidconnection and outwardly of each of said lower draft arms to therebyengage said arms and cam inwardly and confine said lower draft arms to alaterally confined movement when said draft arms are pivotally raised.

2. A sway limiting device for use with a vehicle three point hitch asset forth in claim 1 wherein said cam means defines said surfacedivergent outwardly and downwardly for camming said lower draft armsinrearwardly of said connecting means to thereby permit lateral sway ofthe draft arms when said draft arms are in the lowered position.

4. A sway limiting device for use in a vehicle three point hitch as setforth in claim 1 wherein said inner sway limiting means includes hangerbracket means inward of said draft arms, said hanger bracket meansincluding sway blocks limiting the inward sway of said point hitch asset forth in claim 4 wherein said sway blocks define'a substantiallyvertical surface to thereby confine the vertical movement of the draftarms substantially between said cam means and said sway blocks.

6. A sway limiting device for use with a vehicle three point hitch asset forth in claim 1 wherein said connecting means defines a ball andsocket permitting said lower draft arms to pivot laterally in theirlower position and to move to a pivotally raised position.

7. A sway limiting device for use in a vehicle three point hitch as setforth in claim 1 wherein said inner sway limiting means means includes adraw bar hanger bracket positioned intermediate said draft arms, swayblocks removably fastened to said hanger bracket defining asubstantially vertical surface to limitthe lateral inward swayingmovement of said draft arms when said draft arms are pivoted to theraised position.

8. A sway limiting device for use in a vehicle three point hitch as setforth in claim 1 wherein said cam means defines said curved surfaceconverging inwardly and upwardly and supporting means supporting saidcam means defining a substantially vertical surface continuous with saidcurvedsurface extending upwardly to confine said draft arms to asubstantially vertical movement when said draft arms are raised.

9. A sway limiting device for use in a vehicle three point hitch as setforth in claim 1 including means positioning said cam means for engagingthe forward portion of each of said draft arms when said draft arms arepivotally raised.

10. A sway limiting device for use with a vehicle three point hitch asset forth in claim 1 including journal means for supporting a torsionbar,'means connecting said lower draft arms eccentrically to saidtorsion bar, means fastening said cam means to said journal means tothereby cam said lower draft arms inwardly when said draft arms areraised.

1. A sway limiting device for use with a vehicle three point hitchcomprising, a pair of rock arms, a pair of lower draft arms, connectingmeans adapted for universally connecting said lower draft arms to avehicle, a single lift link connected between each one of said rock armsand its mating lower draft arm, inner sway limiting means between saiddraft arms limiting the inward sway of said draft arms, cam meansdefining a curved surface in spaced relation rearwardly from saidconnection and outwardly of each of said lower draft arms to therebyengage said arms and cam inwardly and confine said lower draft arms to alaterally confined movement when said draft arms are pivotally raised.2. A sway limiting device for use with a vehicle three point hitch asset forth in claim 1 wherein said cam means defines said surfacedivergent outwardly and downwardly for camming said lower draft armsinwardly when said draft arms are pivotally raised.
 3. A sway limitingdevice for use with a vehicle three point hitch as set forth in claim 1wherein said cam means defines said surface positioned upwardly andrearwardly of said connecting means to thereby permit lateral sway ofthe draft arms when said draft arms are in the lowered position.
 4. Asway limiting device for use in a vehicle three point hitch as set forthin claim 1 wherein said inner sway limiting means includes hangerbracket means inward of said draft arms, said hanger bracket meansincluding sway blocks limiting the inward sway of said draft arms whensaid draft arms are pivotally raised.
 5. A sway limiting device for usewith a vehicle three point hitch as set forth in claim 4 wherein saidsway blocks define a substantially vertical surface to thereby confinethe vertical movement of the draft arms substantially between said cammeans and said sway blocks.
 6. A sway limiting device for use with avehicle three point hitch as set forth in claim 1 wherein saidconnecting means defines a ball and socket permitting said lower draftarms to pivot laterally in their lower position and to move to apivotally raised position.
 7. A sway limiting device for use in avehicle three point hitch as set forth in claim 1 wherein said innersway limiting means means includes a draw bar hanger bracket positionedintermediate said draft arms, sway blocks removably fastened to saidhanger bracket defining a substantially vertical surface to limit thelateral inward swaying movement of said draft arms when said draft armsare pivoted to the raised position.
 8. A sway limiting device for use ina vehicle three point hitch as set forth in claim 1 wherein said cammeans defines said curved surface converging inwardly and upwardly andsupporting means supporting said cam means defining a substantiallyvertical surface continuous with said curved surface extending upwardlyto confine said draft arms to a substantially vertical movement whensaid draft arms are raised.
 9. A sway limiting device for use in avehicle three point hitch as set forth in claim 1 including meanspositioning said cam means for engaging the forward portion of each ofsaid draft arms when said draft arms are pivotally raised.
 10. A swaylimiting device for use with a vehicle three point hitch as set forth inclaim 1 including journal means for supporting a torsion bar, meansconnecting said lower draft arms eccentrically to said torsion bar,means fastening said cam means to said journal means to thereby cam saidlower draft arms inwardly when said draft arms are raised.